ASCII command transmitter
The 1 to 8 button ASCII command transmitter or data string generator was developed for systems and control where we require interfaces from external automated equipment or users. The unit can be incorporated with up to 8 buttons or sensors each programmed to transmit a single character or an entire string when pushed or triggered. The device can also except inputs from other external devices and transmit pre programmed commands to a PC or RS232 communication device. This “RS232 trigger” is used by software developers for projects that require decision making by users or other external devices. It again eases compatibility between systems. Its applications are enormous especially for large factory environments where certain system or machine functions depend on various inputs from users or other control instrumentation. This unit is ideal for the security industry where you would like to override some of the automated functions like boom control by a simple push of a button. Mining operations and industrial automation will also greatly benifit from using this interface. The interface can be modified to work via RS485, USB, CAN, I2C or lan communication protocols.
Example of a 1 and 3 button string generator.
Schematic can be downloaded here using pic 16f84
Firmware can be downloaded here trigger generator
Another version of this project is below, it is far simpler and easier to build
Code can be downloaded here, written in c MPLAB X IDE mplabxide_c